Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Terrestrial, or Tetrapod, Vertebrates — Vertebrates with Embryonic Membranes
Class Aves — Subclass Neornithes, or True Birds — Superorder Palaeognathae, or Ratites — Order Struthioniformes (African Ostriches)

African ostriches are the largest living birds today, represented by a single species — the common ostrich (Struthio camelus) (Fig. 144). Adult males reach up to 270 cm in height. Their body mass averages 50 kg, while the largest males can weigh up to 90 kg. They have only two toes on each FOOT (a unique feature among extant birds). The pubic bones are fused, forming a closed pelvis. Their wings are relatively large, and the birds spread them out when running fast.

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Fig. 144. Ratites:

1 — common ostrich; 2 — cassowary; 3 — kiwi; 4 — rhea; 5 — emu

The overall plumage of males is black, while females are brownish-gray. The feathers on the tail and wings are white. Today, they are distributed across the steppe and desert regions of Africa. During the Paleogene and Neogene periods, closely related species inhabited South Asia, Northern China, Mongolia, Transbaikalia, Northern Kazakhstan, and Ukraine. They inhabit deserts, steppes, and savannas, living in small groups and roaming fairly widely. They are exceptionally fast runners; while running, their stride length can reach 2 — 3 m. They feed primarily on plant matter and, to some extent, small animals (rodents, reptiles, insects). During the breeding season, 3 — 4 females associate with a single male. Males display by throwing their heads back, spreading their wings, crouching, and chasing fleeing females. When defending their territory, males emit a deep roaring sound. The nest is built by the male, into which several females lay eggs, each depositing 7 — 9 eggs. As a result, a single nest may contain 15 — 20 eggs (in North Africa) or even 50 — 60 eggs (in East Africa). An egg weighs 1.5 — 2 kg. The male incubates the eggs at night, and the female during the day. Incubation lasts over 40 days. The chicks hatch downy and precocious with open eyes. They reach sexual maturity in their third year.

Outside the breeding season, they form flocks numbering several dozen birds.

They are sometimes farmed for their ornamental white tail and wing feathers, as well as their palatable meat. In some areas, African ostriches have been heavily hunted and depleted.